Drill



A. P. BRUSH June 26, 1934.

DRILL Filed Aug. 26, 1931' TOR ORNEY v IL atenteol June 2%, llid that rlbbott 1P. Brush, Greenwich, Uonn.

Application August 26, 1931, Serial No. 559,378

' ll (Claim.

This invention relates to various types of hammer drills.

The objects of the invention broadly are to prolong the useful life of hammer drills and to it accomplish this without adding to the expense and in fact by actually reducing the cost of the drill.

The foregoing and other desirable objects are attained by the novel features of construction,

id combination and relation of parts as hereinafter disclosed and broadly claimed.

The drawing accompanying and forming part of this specification illustrates a number of different embodiments of the invention, but as the invention is of such broad scope, it should be understood that further modifications and changes may be made all within the true intent of the invention.

Fig. l is a side elevation of a spiral hammer 241: drill form of the invention and showing, partly in section, a special holder or chuck for this new double-ended or pointed cutting form of hammer drill; Fig. 2 is an elevation of a modified form of the double-ended pointed cutting hammer drill with double lands instead of only the single land shown in Fig. 1; Fig. 3 is an elevation of a further modification in which single lands are provided extending from the opposite ends of the drill to a mid-point.

Figs. l, 5, 6 and '7 are composite views illustrating the invention embodied in different types of hammer drills; Fig. 8 is a detail of another modification.

In Fig. 1 there is illustrated a spiral form of hammer drill 9, differing from standard construction in that in addition to the usual chisel edged hammer cutting point 10, it is formed at the opposite end with a reversely acting chisel edged hammer cutting point 11. This hammer drill has a so-called single land 12, that is at the forward edge of each twist 13. These lands extend in this particular illustration the full length of the twist, that is from the edges 14 at one end to the relieved edges15 back of the edges 16 at the opposite end of the drill. These lands are of service in clearing the hole made by the chisel cutting edges 37, at the opposite ends of the hammer drill.

In the Fig. 2 form of the invention, two lands 12 and 17 are provided on each twist, the first serving primarily when the cutting end 10 of the drill is used and the second when the opposite cutting end 11 is in use.

In the Fig. 3 construction, the land 12 extends 55 only to a mid-point 18 on the drill and the land 17 extends from the opposite end of the drill to a mid-point 19.

In manufacturing these drills, the twist may be formed extending continuously from one end to the opposite end of the drill stock, with one 9 continuous land, or the double lands or single part-length lands and so that when the opposite ends of the drill stock are sharpened, the drill may be reversed end-for-end and used practically its entire length.

To prevent injury or dulling the end cutting edges 3'7, a special chuck or holder is provided, such as illustrated in Fig. 1, having at the end of the bore 20 receiving the drill stock, the oppositely inclined faces 21, 22, designed to bear on the inclined end faces of the drill, back of the cutting edges thereof. This 'holder is shown as split at 23 to receive the chisel edges 3'7 therein and to act in the nature of a spring collet, which when engaged in the chuck of a drill stock will close upon and firmly grip the sides of the drill. This spring collet further is illustrated as of tapered construction at 24, so that it will seat properly in the tapered socket of a drill stock or holder. Also the slot 23 is shown as wide enough to enable a bar or extracting tool being entered therein to loosen the drill in case it should stick in the collet.

In Fig. 4, a drill of flat stock is indicated at 25, widened and pointed at its opposite ends at 26, 2'7, and sharpened at 37 to form equally ef-- fective hammer cutting ends.

In Fig. 5 a star drill 28 is illustrated having the flaring and pointed cutting ribs 29, 30, and sharpened at 37 at opposite ends of the same, enabling use of both ends of the drill.

For special purposes, square or other angular drill stock may be employed. Thus in Fig. 6, a square type of drill stock is indicated at 31, having the opposite ends of the same pointed for drilling purposes at 32, 33, with sharpened hammer cutting edges 37 respectively.

In Fig. 7, a triangular section form of drill stock is shown at 34, having the opposite ends pointed for drilling purposes at 35, 36 and with the sharpened chisel hammer cutting edges 37.

In all forms, the necessity for heading up the drill stock at one end is avoided and the full length of the drill stock is utilized for drill purposes. Consequently, this new hammer drill has practically double the useful life of an ordinary hammer drill and it can be produced at less or no greater cost than an ordinary hammer drill. Being without the enlargement of a squared or otherwise shaped driving head, the drill takes up less space. Especially important is the fact that when dulled at one end, the drill may be instantly reversed end-for-end to present new or sharp cutting edges, thus enabling work to be continued on a job where time or facilities for sharpening would be outof the question.

Also the tool may be constructed for forming different sized openings; Thus as shown in Fig. 8, one end of the drill 10a may be made larger than the other end 11a, so that by reversal of the tool end-for-end either of the two sized holes may be drilled.

All forms of the invention involve the same one piece drill stock provided at opposite ends with lengthwise sharpened chisel-like hammer drill cutting edges, so that either end and both ends may be used as a hammer drill with the intermediate part of the drill stock between the oppositely sharpened hammer drill ends provideeaoec hammer drill cutting edges andthe intermediate portion of the drill stock between said opposite end lengthwise sharpened hammer drill cutting edges being of hammer dr stock formation and providing for proper holding of the drill regardless of which end of the drill is used for ham mer drill cutting purposes.

BUTT P. BRUSH. 

